Circuit reduces PS noise by up to 26db

[gasboss775]

I thought This Article might be of interest.

It is claimed the circuit reduces power rail noise by up to 26db.

 

[AndrewT]

does it show any similarities to JLH ripple eater?

 

[JonSnell Electronic]

I don't think that shunting a low impedance power supply with a FET and 200R will do anything.
Rs + R1 = 0R1 each so 50% regulation BUT R2 is 200R so no regulation!
Someone has the wrong idea. Most series regulators have a feedback loop that reduces noise. A 10uF Tant Bead capacitor will filter out most if not all HF noise, if indeed there is any there in the first place. That is what Cout does.http://www.ti.com/lit/ds/symlink/tps54120.pdf

 

[dmills]

That is basically the opamp and fet version of Charlie Wenzels circuit.

Finesse Voltage Regulator Noise! |

The operation is actually a little subtle, in that the circuit is a current sink which sinks current equal to the noise current flowing in R1, R2 is I think a safety resistor so the fet turning hard on at startup does not short the supply, it takes no part in normal operation.

Regards, Dan.

 

[gasboss775]

does it show any similarities to JLH ripple eater?

Andrew, thanks for bringing the JLH circuit to my attention.

It would seem to be broadly the same idea to the one I posted, though in the JLH circuit instead of the ccs shunting the output side of the 0.1R Rs, it shunts the output of the power supply relying on the power supplies own internal source resistance instead.

I have attached what I think is equivalent to the two circuits. As you can see they are very similar in concept. I'm not sure about the subtleties of the two very different realizations of what is a very similar concept. I expect that from an audio perspective it would need to be listened to, in addition to objective measurements of noise reduction.